Unconventional Natural Gas Potential in Saudi Arabia

Abstract Surge in the worldwide demand for natural gas, in recent years, has resulted in a considerable interest in the unconventional natural gas resources in many countries, including Saudi Arabia. Numerous studies indicate that the supply and demand balance can be achieved through the exploitation of unconventional resources which are located in the major hydrocarbon basins of the world. The scope of this paper is to review the main sources of unconventional natural gas with some emphasis on potential resources in the Arabian Peninsula, and to present initial results derived from a recent study of Paleozoic formations in the Rub’ Al-Khali Basin. Besides contributing to the general knowledge on unconventional natural gas resources, the information provided in this paper is expected to guide current exploration activities on the unconventional natural gas in Paleozoic formations in the Rub’ Al-Khali Basin. Based on the lognormal model, it has been demonstrated that the volume of unconventional gas resources in a particular basin is several times that of the proved reserves in that basin. Considering this model, it is possible to deduce that vast amounts of unconventional resources exist in the Arabian Peninsula. Potential targets have been identified to be the Paleozoic formations, including Qasim, Sarah, Qalibah, Jauf, Unayzah, and Khuff. Average porosity and permeability measurements, based on the combined data from several vertical wells intersecting each formation in the Rub’ Al-Khali Basin, have been compared with the corresponding published data from the producing tight gas formations from North American basins. Porosity and permeability values, representing various formations in the Rub’ Al-Khali Basin, compare well with the corresponding parameters from North American basins. The same data, also, revealed the differences and similarities of patterns of distributions of petrophysical parameters in formations under consideration. Major technical contributions of this paper include: (1) appraisal of distribution of unconventional natural gas resources in the Arabian Peninsula, (2) characterization of natural gas potential of various formations, and (3) comparison of petrophysical parameters with the corresponding values from similar basins from North America.